1. Field of the Invention
The present invention relates to a two-chamber cartridge for liquids, particularly for drug formulations for use in propellant-free metering aerosols.
2. Description of Related Art
International Patent Application WO91/14468 “Atomizing Device and Methods” describes a device for propellant-free administration of a metered quantity of a liquid pharmaceutical composition for use by inhalation. A further developed embodiment is described, for example, in PCT/EP96/04351. For applications of this kind it is required to package the solutions containing the active substance into containers in such a way as to include only tiny residues of air and gas. Gas bubbles would lead to uncertainty in the accurate metering of the active substance. Containers of this kind are disclosed for example in International Patent Application PCT/EP95/03183. The containers described therein are particularly suitable for those pharmaceutical compositions which can be stored for lengthy periods in the form of an aqueous or ethanolic solution. For active substances which decompose in their solutions after only a few months there have not hitherto been any suitable containers which would allow commercial use of such sensitive preparations in propellant-free metering aerosols.